school, if any, to sign a "copyright disclaimer" for the library, if
necessary.  Here is a sample; alter the names:

  Yoyodyne, Inc., hereby disclaims all copyright interest in the
  library `Frob' (a library for tweaking knobs) written by James Random
  Hacker.

  {signature of Ty Coon}, 1 April 1990
  Ty Coon, President of Vice

## More motivation

Check this function, it already has type hints:

```Python hl_lines="1"
{!../../../docs_src/python_types/tutorial003.py!}
```

Because the editor knows the types of the variables, you don't only get completion, you also get error checks:

<img src="/img/python-types/image04.png">

Now you know that you have to fix it, convert `age` to a string with `str(age)`:

them.

  `I'm sure I'm not Ada,' she said, `for her hair goes in such
long ringlets, and mine doesn't go in ringlets at all; and I'm
sure I can't be Mabel, for I know all sorts of things, and she,
oh! she knows such a very little!  Besides, SHE'S she, and I'm I,
and--oh dear, how puzzling it all is!  I'll try if I know all the
things I used to know.  Let me see:  four times five is twelve,

   */
  @Throws(IOException::class)
  fun authenticate(
    route: Route?,
    response: Response,
  ): Request?

  companion object {
    /** An authenticator that knows no credentials and makes no attempt to authenticate. */
    @JvmField
    val NONE: Authenticator = AuthenticatorNone()

    private class AuthenticatorNone : Authenticator {
      override fun authenticate(

    locking. That's a potential security vulnerability, tracked as [CVE-2022-24329].
 *  Upgrade: [publicsuffix.org data][public_suffix]. This powers `HttpUrl.topPrivateDomain()`.
    It's also how OkHttp knows which domains can share cookies with one another.
 *  Upgrade: [Okio 3.2.0][okio_3_2_0].


## Version 4.10.0

_2022-06-12_

 *  Upgrade: [Kotlin 1.6.20][kotlin_1_6_20].
 *  Upgrade: [Okio 3.0.0][okio_3_0_0].

      clientTestRule.newClientBuilder()
        .proxy(socksProxy.proxy())
        .build()
    val url =
      server.url("/")
        .newBuilder()
        .host(SocksProxy.HOSTNAME_THAT_ONLY_THE_PROXY_KNOWS)
        .build()
    val request = Request.Builder().url(url).build()
    val response1 = client.newCall(request).execute()
    assertThat(response1.body.string()).isEqualTo("abc")

if "johndoe" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

But right at the moment Python compares the first `j` in `johndoe` to the first `s` in `stanleyjobson`, it will return `False`, because it already knows that those two strings are not the same, thinking that "there's no need to waste more computation comparing the rest of the letters". And your application will say "Incorrect username or password".

```Python hl_lines="2"
# This is not asynchronous
def get_sequential_burgers(number: int):
    # Do some sequential stuff to create the burgers
    return burgers
```

With `async def`, Python knows that, inside that function, it has to be aware of `await` expressions, and that it can "pause" ⏸ the execution of that function and go do something else 🔀 before coming back.

          val domainName = fromSource.readUtf8(domainNameLength.toLong())
          // Resolve HOSTNAME_THAT_ONLY_THE_PROXY_KNOWS to localhost.
          when {
            domainName.equals(HOSTNAME_THAT_ONLY_THE_PROXY_KNOWS, ignoreCase = true) -> {
              InetAddress.getByName("localhost")
            }
            else -> InetAddress.getByName(domainName)
          }
        }

<img src="/img/tutorial/response-status-code/image01.png">

!!! note
    Some response codes (see the next section) indicate that the response does not have a body.

    FastAPI knows this, and will produce OpenAPI docs that state there is no response body.

## About HTTP status codes

!!! note
    If you already know what HTTP status codes are, skip to the next section.